This invention relates to turbines. A turbine is, of course, a device for taking power from a working fluid. To the extent to which turbines can also be run as pumps, or compressors, imparting power from an external rotary source to a working fluid, the invention also relates to pumps or compressors. Where reference is made to "turbine" herein, it is to be understood as applying wherever possible to pumps and compressors as well.
There are several recognised types of turbines, amongst which may be mentioned axial flow turbines typified by the turbines of jet aircraft engines and gas turbine and steam power plants driving large electric generators. These axial flow turbines comprise a plurality of discs having radially extending peripheral blades. The blades are attached to the discs in a variety of ways, often having specially shaped blade roots which fit into correspondingly shaped slots in the disc periphery. The blades have to be individually fashioned and fitted and the construction is complicated and expensive and, as a matter of commercial practicality, essentially confined to the high performance uses referred to.
Another type of turbine is the tangential flow turbine which is in essence like a water wheel in which the working fluid is introduced tangentially to impinge upon vanes at the periphery of a rotary disc member.
Either of these types may be a reaction turbine or an impulse turbine, depending on the blade configuration. In an impulse turbine, the working fluid is directed at a rotary blade with the intention to hit it square-on, so to speak, and impart kinetic energy to the blade through the loss of momentum of the working fluid. In a reaction turbine, the blades are fashioned so as to act more like aerofoil sections and increase the speed of the working fluid over the concave face of the blade as compared to the convex face, whereby to generate "lift" in the tangential direction so as to drive the disc member in rotation.
As a practical matter, most turbines operate partly as impulse and partly as reaction turbines, depending on the operating conditions.
The tangential flow turbine, in any event, whilst generally speaking being of less complicated construction than the axial flow turbine, still is a costly machine to engineer, requiring, again, individual blade or vane construction and location.
The present invention provides a turbine that is, by contrast, extremely simple and inexpensive to manufacture.